Inspection and characterization of birefringent materials: development of methods and systems for scintillating anisotropic crystals

Un cristallo scintillatore ha la peculiare capacità di convertire, in luce visibile, l'energia di una particella radiante che interagisce con il suo volume. L'eccitazione può derivare da diversi tipi di radioattività o interazione energetica che è in grado di eccitare gli elettroni in modo da farli saltare ad una banda di energia più alta e tornare indietro al loro stato di equilibrio. Questo meccanismo porta ad un rilascio di fotoni nel visibile (e vicino visibile). La luce prodotta dal cristallo è solitamente monocromatica e rappresenta il prodotto della conversione dell'energia incidente in energia di un gruppo di fotoni di energia molto inferiore quelli assorbiti, come avviene per tutti i tipi di conversione di energia. La qualità della luce emessa da questi materiali, in termini di stabilità di lunghezza d'onda, coerenza e polarizzazione, è estremamente elevata. Essi sono coinvolti in campi come la fisica nucleare e la fisica delle alte energie (ad esempio, CERN-Ginevra), in campo medico nell’ambito del bio-immaging (tomografia ad emissione di positroni PET-per la diagnosi del cancro), la ricerca geologica, la sicurezza e la tecnologia laser. Le prestazioni degli scintillatori incide sul comportamento degli strumenti e dei sistemi sfruttati in tali settori; Inoltre, la qualità del materiale stesso e l'efficienza di produzione, determinano il costo e la fattibilità delle suddette attività. Una conoscenza approfondita e una buona caratterizzazione del materiale è fondamentale per prevedere il comportamento dei cristalli dal punto di vista sia meccanico che ottico. Poiché il processo di produzione è piuttosto complesso, delicato e lungo, l'industria ha bisogno di strumenti per migliorare l'efficienza e l'efficacia della produzione di questi scintillatori cristallini Il lavoro presentato in questa tesi mira allo sviluppo di metodi e sistemi non invasivi per valutare la qualità dei cristalli attraverso la determinazione dello stato di stress residuo, che può essere una firma del grado di qualità. I metodi sviluppati sono basati sulla fotoelasticità e la cristallografia ottica; permettono un'analisi molto dettagliata con elevata sensibilità e risoluzione spaziale. La possibilità di avere una caratterizzazione completa dei materiali è stata migliorata riuscendo a misurare in direzione diversa rispetto agli assi ottici del cristallo. L'insieme di metodi sviluppati è completata da una nuova tecnica denominata Sfenoscopia, che fornisce controlli affidabili del cristallo in un modo più veloce e semplificato ed in qualunque orientamento rispetto agli assi ottici. Dal momento che i metodi si basano sulla acquisizione di immagini di frange, i sistemi sono stati forniti di algoritmi dedicati per elaborare e analizzare accuratamente le immagini acquisite. Le informazioni ottenute con questi metodi sono utili sia per gli enti di ricerca che per le industrie, produttori e utenti finali. Esse sono fondamentali per avere la possibilità di comprendere meglio il comportamento del materiale, sviluppando modelli matematici predittivi, per impostare correttamente i parametri di produzioneA scintillating material has the peculiar capability to convert in visible light the energy of a radiating particle that interact within its volume. The excitation can derive from different kinds of radioactivity or energy interaction that is able to excite electrons so to make them jump to a higher energy band and turn back to their equilibrium state. This mechanism leads to a release of photons in the visible (or near-visible) range. The light produced by the scintillating material is usually monochromatic and represents the output of the conversion of the incident energy in the energy of a group of photons each of much lower energy than one absorbed, as it happens for all kinds of energy conversion. The quality of light emitted by these materials has, also, great quality in terms of wavelength stability, coherence and polarization. They are involved in fields like the nuclear and high energy physics (for instance, CERN-Geneva), medical and general bio-imaging (PET-positron emission tomography for cancer diagnosis), geologic research, security and laser technology. Performances of the scintillators rule the behavior of the instruments and the systems exploited in those fields; moreover, the quality of the material itself and the production efficiency, determine the cost and the feasibility of the above-mentioned activities. In depth knowledge and characterization of the material is crucial to predict the behavior of the crystals from mechanical and optical viewpoint. Since the production process is quite complex, delicate and time consuming, industry needs tools to improve the efficiency and efficacy of the larger and larger production of these crystalline scintillators The work presented in this thesis aims to the development of non-invasive methods and systems to assess the crystal quality through the determination of the residual stress state that can be the signature of the whole quality degradation due to different origins. The developed methods are based on photoelasticity and optical crystallography; they allow to a very detailed analysis providing sensitivity and spatial resolution. The possibility to have a complete characterization of the materials has been improved by the measuring in different direction with respect to the crystal optic axes. The set of developed methods is completed by a new technique named Sphenoscopy, which provides reliable inspection of the crystal in a faster and simplified way whatever orientation of the crystallographic and optic axes. Since they are based on the acquisition of fringe images, -the systems have been provided of dedicated algorithms to process and analyze accurately the fringe patterns carried out by the methods. The information carried out by these methods are useful for both research bodies and industries, crystal producers and users, since they are crucial feedbacks to better understand the material behavior, develop predictive math models and set properly the production parameters

The Refraction Indices and Brewster Law in Stressed Isotropic Materials and Cubic Crystals

none4noWe study the elasto-optic behavior of stressed cubic crystals (all classes) and isotropic materials (like e.g. glasses). We obtain the explicit dependence of the refraction indices on the stress (either applied or residual), as well as a mild generalization of the Brewster law for cubic crystals. We show also that the optic indicatrix and the stress ellipsoid are coaxial only in the isotropic case. This theory allows the improvement of the measurements techniques, as photoelasticity, on cubic crystals and optically isotropic materials.openDaniele Rinaldi,Pier Paolo Natali, Luigi Montalto,Fabrizio DavìRinaldi, Daniele; Natali, PIER PAOLO; Montalto, Luigi; Davi', Fabrizi

Acoustic Attenuation of COVID-19 Face Masks: Correlation to Fibrous Material Porosity, Mask Breathability and Bacterial Filtration Efficiency

none7openMartarelli, Milena; Montalto, Luigi; Chiariotti, Paolo; Simoni, Serena; Castellini, Paolo; Battista, Gianmarco; Paone, NicolaMartarelli, Milena; Montalto, Luigi; Chiariotti, Paolo; Simoni, Serena; Castellini, Paolo; Battista, Gianmarco; Paone, Nicol

Clinical course and management of acute and chronic viral hepatitis during pregnancy.

Pregnancy is a para-physiologic condition, which usually evolves without any complications in the majority of women, even if in some circumstances moderate or severe clinical problems can also occur. Among complications occurring during the second and the third trimester very important are those considered as concurrent to pregnancy such as hyperemesis gravidarum, intrahepatic cholestasis of pregnancy, HELLP syndrome and acute fatty liver of pregnancy. The liver diseases concurrent to pregnancy typically occur at specific times during the gestation and they may lead to significant maternal and foetal morbidity and mortality. Commonly, delivery of the foetus, even preterm, usually terminates the progression of these disorders. All chronic liver diseases, such as chronic viral hepatitis, autoimmune hepatitis, Wilson's disease, and cirrhosis of different aetiologies may cause liver damage, independently from pregnancy. In this review we will also comment the clinical implications of pregnancies occurring in women who received a orthotopic liver transplantation (OLT) Therefore, the management of immunosuppressive therapy before and after the delivery in women who received liver transplant is becoming a relevant clinical issue. Finally, we will focus on acute and chronic viral hepatitis occurring during pregnancy, on management of advanced liver disease and we will review the literature on the challenging issue regarding pregnancy and OLT

Rivaroxaban-induced hepatotoxicity: review of the literature and report of new cases

Aim/Objective/Background Direct-acting oral anticoagulant drugs are marketed worldwide for the primary and secondary prevention and treatment of thromboembolic disorders. Rivaroxaban, an oral, direct factor Xa inhibitor, is one of the most used. Rivaroxaban-induced hepatotoxicity is unusual, although a number of adverse reports have recently been reported. Here, we report two new cases of rivaroxaban-induced hepatitis. Methods A systematic search of case reports on the MEDLINE database encompassing the years 2008–2016 was carried out.Additional references were obtained following a manual search of the retrieved papers. We report two new cases of adverse events occurred in patients treated with rivaroxaban (20 mg/die) to prevent systemic embolism, who presented with hepatocellular liver injury with onset at 8 weeks after initiation of the drug intake. Results Twenty-six cases were retrieved from MEDLINE (57.7% female, 42.3% male). Using the Roussel Uclaf Causality Assessment Method (RUCAM) scale, liver injury was classified as hepatocellular (42.3%), cholestatic (26.9%), or mixed (15.4%). Older age (≥65 years) was present as a risk factor in 57.7%. The time lapse between initiation of treatment and onset of hepatic injury ranged from 2 to 180 days (median: 15 days). Our two new patients were diagnosed with drug-induced liver injury (hepatocellular pattern) using the ‘consensus criteria’, for drug-induced liver injury. Their RUCAM scores were calculated and assessed as highly probable and probable, respectively. A clinical recovery after rivaroxaban withdrawal was observed. Conclusion Direct-acting oral anticoagulants have been commonly prescribed, even if safety issues regarding the use of these drugs are still an ongoing concern, especially in patients experiencing chronic liver disease. Dedicated postauthorization safety studies should be undertaken to better define rivaroxaban-induced drug-induced liver injury

Luminescence and Structural Characterization of Gd2O2S Scintillators Doped with Tb3+, Ce3+, Pr3+ and F for Imaging Applications

none14siRadiodiagnostic technologies are powerful tools for preventing diseases and monitoring the condition of patients. Medicine and sectors such as industry and research all use this inspection methodology. This field demands innovative and more sophisticated systems and materials for improving resolution and sensitivity, leading to a faster, reliable, and safe diagnosis. In this study, a large characterization of gadolinium oxysulfide (Gd2O2S) scintillator screens for imaging applications has been carried out. Seven scintillator samples were doped with praseodymium (Pr3+), terbium (Tb3+) activators and co-doped with praseodymium, cerium, and fluorine (Gd2O2S:Pr,Ce,F). The sample screens were prepared in the laboratory in the form of high packing density screens, following the methodology used in screen sample preparation in infrared spectroscopy and luminescence. Parameters such as quantum detection efficiency (QDE), energy absorption efficiency (EAE), and absolute luminescence efficiency (ALE) were evaluated. In parallel, a structural characterization was performed, via XRD and SEM analysis, for quality control purposes as well as for correlation with optical properties. Spatial resolution properties were experimentally evaluated via the Modulation Transfer Function. Results were compared with published data about Gd2O2S:Pr,Ce,F screens produced with a standard method of a sedimentation technique. In particular, the ALE rose with the X-ray tube voltage up to 100 kVp, while among the different dopants, Gd2O2S:Pr exhibited the highest ALE value. When comparing screens with different thicknesses, a linear trend for the ALE value was not observed; the highest ALE value was measured for the 0.57 mm thick Gd2O2S:Pr,Ce,F sample, while the best MTF values were found in the thinner Gd2O2S:Pr,Ce,F screen with 0.38 mm thickness.De Martinis, Alessia; Montalto, Luigi; Scalise, Lorenzo; Rinaldi, Daniele; Mengucci, Paolo; Michail, Christos; Fountos, George; Martini, Nicki; Koukou, Vaia; Valais, Ioannis; Bakas, Athanasios; Fountzoula, Christine; Kandarakis, Ioannis; David, StratosDe Martinis, Alessia; Montalto, Luigi; Scalise, Lorenzo; Rinaldi, Daniele; Mengucci, Paolo; Michail, Christos; Fountos, George; Martini, Nicki; Koukou, Vaia; Valais, Ioannis; Bakas, Athanasios; Fountzoula, Christine; Kandarakis, Ioannis; David, Strato

Clinical governance of patients with acute coronary syndromes

Aims Using the principles of clinical governance, a patient-centred approach intended to promote holistic quality improvement, we designed a prospective, multicentre study in patients with acute coronary syndrome (ACS). We aimed to verify and quantify consecutive inclusion and describe relative and absolute effects of indicators of quality for diagnosis and therapy. Methods and results Administrative codes for invasive coronary angiography and acute myocardial infarction were used to estimate the ACS universe. The ratio between the number of patients included and the estimated ACS universe was the consecutive index. Co-primary quality indicators were timely reperfusion in patients admitted with ST-elevation ACS and optimal medical therapy at discharge. Cox-proportional hazard models for 1-year death with admission and discharge-specific covariates quantified relative risk reductions and adjusted number needed to treat (NNT) absolute risk reductions. Hospital codes tested had a 99.5% sensitivity to identify ACS universe. We estimated that 7344 (95% CI: 6852-7867) ACS patients were admitted and 5107 were enrolled-i.e. a consecutive index of 69.6% (95% CI 64.9-74.5%), which varied from 30.7 to 79.2% across sites. Timely reperfusion was achieved in 22.4% (95% CI: 20.7-24.1%) of patients, was associated with an adjusted hazard ratio (HR) for 1-year death of 0.60 (95% CI: 0.40-0.89) and an adjusted NNT of 65 (95% CI: 44-250). Corresponding values for optimal medical therapy were 70.1% (95% CI: 68.7-71.4%), HR of 0.50 (95% CI: 0.38-0.66), and NNT of 98 (95% CI: 79-145). Conclusion A comprehensive approach to quality for patients with ACS may promote equitable access of care and inform implementation of health care delivery. Registration ClinicalTrials.Gov ID NCT0425553

Impact of safety-related dose reductions or discontinuations on sustained virologic response in HCV-infected patients: Results from the GUARD-C Cohort

BACKGROUND: Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice. METHODS: A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the impact of sr-RD on SVR24 (HCV RNA <50 IU/mL) were conducted in 951 Caucasian, noncirrhotic genotype (G)1 patients assigned to peginterferon alfa-2a/ribavirin for 48 weeks. The probability of SVR24 was identified by a baseline scoring system (range: 0-9 points) on which scores of 5 to 9 and <5 represent high and low probability of SVR24, respectively. RESULTS: SVR24 rates were 46.1% (754/1634), 77.1% (279/362), 68.0% (514/756), and 51.3% (203/396), respectively, in G1, 2, 3, and 4 patients. Overall, 16.9% and 21.8% patients experienced 651 sr-RD for peginterferon alfa and ribavirin, respectively. Among Caucasian noncirrhotic G1 patients: female sex, lower body mass index, pre-existing cardiovascular/pulmonary disease, and low hematological indices were prognostic factors of sr-RD; SVR24 was lower in patients with 651 vs. no sr-RD by Week 4 (37.9% vs. 54.4%; P = 0.0046) and Week 12 (41.7% vs. 55.3%; P = 0.0016); sr-RD by Week 4/12 significantly reduced SVR24 in patients with scores <5 but not 655. CONCLUSIONS: In conclusion, sr-RD to peginterferon alfa-2a/ribavirin significantly impacts on SVR24 rates in treatment-naive G1 noncirrhotic Caucasian patients. Baseline characteristics can help select patients with a high probability of SVR24 and a low probability of sr-RD with peginterferon alfa-2a/ribavirin

Clinical anatomic, immunomorphologic and molecular anatomic data suggest interplay of thyroidal molecules, autoantibodies and Hsp60 in Hashimoto’s disease

Hsp60 is, typically, a mitochondrial protein, but it also occurs in the cytosol, vesicles, and plasma membrane, and in the intercellular space and biological fluids, e.g., blood. Changes in the levels and distribution of Hsp60 are linked to several pathologies, including cancer and chronic inflammatory and autoimmune disorders. What is the histopathological pattern of Hsp60 in the thyroid of Hashimoto’s patients? Are there indications of a pathogenic role of Hsp60 that may make Hashimoto’s thyroiditis a chaperonopathy? Experiments reported here provide information regarding those questions. We found by various immunomorphological techniques increased levels of Hsp60 in the thyroid from HT patients, localized to thyrocytes of small and degenerated follicles and to oncocytes (Hurtle cells). Immunofluorescence showed the chaperonin both inside the cells and also in the plasma membrane, especially in oncocytes. We also found that Hsp60 levels in the blood of HT patients were increased compared to controls and correlated with those of autoantibodies against two distinctive thyroidal proteins, thyroglobulin (TG) and thyroid peroxidase (TPO) (r=0.379, p=0.0103; r=0.484, p=0.0008; respectively). Molecular analysis of these two proteins in comparison with Hsp60 demonstrated various regions of high structural similarity shared by them, which could very well be immunologically crossreactive epitopes. Thus, it is likely that the three proteins potentiate each other as immunogens to elicit autoantibodies and, as antigens, to cause antigen-antibody reactions at those sites in which Hsp60 is exposed, for example the surface of oncocytes. This would lead to inflammation and oncocyte lysis with destruction of thyroidal tissue. The cytometric bead assay revealed that recombinant Hsp60 did not induce increment of cytokine production by peripheral blood mononuclear cells from HT patients. Consequently, we propose that Hsp60 is implicated in the pathogenesis of Hashimoto’s thyroiditis as autoantigen, via a participation of autoantibodies that also recognize TG and TPO, whereas participation of inflammatory cytokines induced by the chaperonin is unlikely. Supported by IEMEST (FC and AJLM)